The invention relates to a portable electronic device having means for entering characters and has particular, but not exclusive, application to portable radio devices such as mobile telephones, data terminals and pagers, and to hand held computers.
Portable electronic devices such as mobile telephones are being designed increasingly small. In parallel, there is an increasing requirement for entering characters such as alphanumeric text into such devices, for example for email communication while on the move. As a result there is a need for a small-sized man-machine interface that is easy to operate and can handle typically 40 or more characters.
One known way of achieving miniaturisation is to use small keys, which, for example, may be arranged in the standard QUERTY keyboard configuration. However, as portable electronic devices are made smaller, such a miniaturised keyboard configuration becomes increasingly difficult to operate.
Another known way of achieving small size is to reduce the number of keys by using multi-character keys in which repeated presses of a key, or continuous pressing of a key for different durations, results in different characters being entered.
Yet another known method is to use cursor control keys and an xe2x80x98enterxe2x80x99 key to select characters from a displayed alphabet.
The latter two methods can be slow and prone to error.
A further method disclosed in EP 0840934 B uses a single press of a multi-character key to enter each character, in which the point of pressure determines which character is entered. However, entering characters quickly and accurately using a plurality of such keys requires skill and practice.
An object of the invention is to provide improvements in entering characters into portable electronic devices.
According to the invention there is provided a portable electronic device having character selecting means for selecting characters for entry into the device, the character selecting means comprising a first key and a plurality of second keys, the first key having N switch contracts, where N greater than 2, and each of the plurality of second keys having a single switch contact, wherein one of N characters may be selected by engaging in combination one of the N switch contacts of the first key and the single switch contact of one of the plurality of second keys.
In one embodiment of the invention the first key has four switch contacts, for example implemented in a four-way rocker switch, in which the four contacts are deployed radially about the centre of the switch.